How do I fit these creatures into my world?

For my fantasy world, I am trying to stick to one source for mythical creatures, The Book of Imaginary Beings, that being the first book on mythical creatures I received. I have weeded out a few I am going to not use, but I also want to know how the ones I want to use are to be used. A few tips please?

​

The list.

​

Baldanders- A German shapeshifter supposedly based on the Greek Demigod Proteus, whose symbol is the crescent moon and teaches a hero named Simplicissimus how to conserve with inanimate objects.

Double- The exact replica of a person, often seen either a portent of death or proof that you had attained prophetic powers.

The Fauna of Mirrors- A collective group of species who, after a long bloody war with us, were cast out by the Yellow Emperor's Magic and trapped in mirrors. There will come a day where they will break out of the mirror and wage war. Examples of Fauna are the Tigers and Fish of the Mirrors, the latter being coloured in an unknown colour.

Hochigan- In South Africa, a bushman who stole the speech of animals, who at the time were able to talk.

A King Of Fire- In Paradise Lost, a king made of fire with a steed that is 'Not horse, nor hippogriff, nor drake'.

Lamed Wufniks- 36 men who are very poor and aim to spread the word of God, although if they learn what they are, they die and another immediately takes their place.

Lemures- The evil spirits who constantly tormented the living, so much so that the legendary founder of Rome, Romulus, made a festival first to appease the ghost of his dead brother, Remus, and then all the ghosts.

Lilith- A female demon and Adam's first wife, who tempted Eve in the form of a snake, but often appears as a tall, silent dark haired woman.

The monster Acheron- A living representation of hell bigger than any mountain, with three throats that belch fire, with the souls of the damned constantly wailing inside, filled with beasts, or as Borges says, a beast with other beasts inside it.

Mother of Tortoises- A giant tortoise supposedly made of fire and water which showed a cosmic treaty on its back to the Chinese Emperor Yu(umlaut on the u).

Norns- three beings in Norse mythology who respectively make the past, present and future. They are alluded to in Macbeth as the 'weird sisters'.

Simurgh- A giant bird which is immortal, king of all birds and the father of a Persian Hero.

Talos- A giant of bronze who would either throw boulders or heat his body and burn someone by embrace.

The Valkyries- Winged warrior maidens, the valkyries were the choosers of the dead, picking who would go to Valhalla.

Hello, I know a lot of people post this kind of thing but I enjoy reading through them so I hope someone will enjoy reading through mine! Just looking for general feedback on my worldbuilding, or if you've got any ideas. The Scepturi are magical beings from a different dimension…

Hi. My trilogy’s world is very low fantasy. I intended to have absolutely no magic aside from the gods and their abilities, but I’ve included some very low/soft magic elements that come up only a handful of times. Non-trilogy works set in this world thus far have absolutely no magic…

Hey all, Somewhat rookie writer here, about to plunge into my second novel. This particular one will be a very grounded space western, focused on our struggle to colonize the entire solar system, along with conflicts between Earth and ex-earth governments, interplanetary smugglers, the rich and the poor on Mars,…